As the first mammal to be cloned from an adult cell, Dolly made headlines around the world when she was born at the Roslin Institute near Edinburgh in 1996.She was hailed as a scientific sensation but critics warned the technology brought with it a high risk of miscarriage and still birth – and for those creatures that did survive, ill health and premature death.The need to put Dolly down aged only six, to end her suffering from advanced lung disease and arthritis, further inflamed fears about the long-term health of cloned animals.The latest experiments were partly carried out to check if improvements to the technique cut the risk of problems in and out of the womb.HOW THEY MADE HISTORYAs the first mammal to be cloned from an adult cell, Dolly the sheep was a scientific sensation.To make her, Professor Campbell and then colleague Professor Ian Wilmut started with cells taken from the udder of an adult ewe.The nuclei - the blobs at the centre which contain a complete set of DNA - were removed and injected into hollowed-out eggs taken from other sheep.The eggs were then zapped with electricity to trick them into growing and developing like a normal embryo. After a few days the scientists took the healthiest embryos and implanted them into a surrogate mother.In all, 277 eggs were used to produce 29 embryos and only one lamb - Dolly - survived.The recycling of the genetic material from the udder meant that Dolly was an exact genetic duplicate of the ewe that donated the breast tissue. And as the same genetic material was used this time round, the Dollies are exact copies of Dolly and of the ewe.Named after country and western singer Dolly Parton, Dolly was created from a cell taken from a mammary gland. The rest of the sample of tissue has lain in a freezer since, until it was defrosted to make the Dollies.This means the quads are genetically identical to each other, as well as to Dolly, and to the ewe that donated the udder tissue. Professor Keith Campbell, who keeps the Dollies as pets on land at Nottingham University, said: ‘Dolly is alive and well. Genetically these are Dolly.’The cloning of Dolly was a long and tortuous process. In all, 277 eggs were used and only one lamb – Dolly – survived.This time, only five embryos were needed to produce each one of the Dollies.Professor Campbell said the health of the clones was being closely watched. He added: ‘They have got the life of Reilly – they potter around and get fed.‘We are not doing anything to them, they have no health concerns and they show none of the signs of developing the arthritis that Dolly had.’The professor, who plans to publish details about the Dollies in a scientific journal, said improvements in the technology raised the odds of clones being born alive and healthy but admitted the method was still not perfect.Animal welfare campaigners say that cloned animals and their surrogate mothers still suffer immensely.Peter Stevenson, of Compassion in World Farming, said: ‘Cloning is a welfare disaster.’The Dollies were born three-and-a-half years ago but their existence became public only when Professor Campbell mentioned them during a lecture at a recent EuropeanParliament debate on cloning and animal welfare.He said he had not tried to hide their existence and had spoken of the animals to other scientists.Despite controversy over animal welfare, cloning is used in agriculture to make copies of prize-winning animals, allowing them to be bred from over and over again.It is also of interest to stem cell scientists and to those trying to create designer animals that produce medicines in their milk.Read more: http://www.dailymail.co.uk/sciencetech/article-1334201/Dolly-reborn-Four-clones-created-sheep-changed-science.html#ixzz16zGIulZ6
